Liquid-fuel supply system



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EJA. REID LIQUID FUEL SUPPLY SYSTEM Filed March 16, 1927 2 Shets-Sheet 1 //VVf/V70IP Ernest Andrew R i Jaaa. 15, 1929.

E. A. REID LIQUID FUEL SUPPLY SYSTEM Filed March 16, 1,927 2 Sheets-Sheet 2 awn 7a,?

Erneet An drew Wei Patented Jan. 15, 1929.

rinse STATES PATENT ERNEST ANDREW REID, OF LONDON, ENGLAND, ASSIGIIOR OF ONE-I-IALF 'IO FILMA OIL BURNERS LIMITED, OF LONDON ENGLAND, A COMPANY OF GREAT BRITAIN.

LIQUID-FUEL SUPPLY SYSTEM.

Application filed March 16, 1927, Serial No. 175,896, and in Great Britain May 19, 19536.

This invention relates to systems for feeding liquid fuel to burners arranged to heat water of the type in which the liquid fuel is supplied to the burner under pressure, and it is particularly concerned with small hot water heaters where oil is fed to a burner under very small pressures applied to the oil in a container by means of a rotary air pump or the like driven by an electric motor.

In such systems which are used, for example, for heating domestic hot water and the like where the temperature varies only between about 32 and 200 F., it is, of course, impossible; to control the fuel supply by means of variations in pressure of the liquid heated or of its vapour.

It is the object of the present invention to include within the liquid fuel supply system such as is set forth above, a control device arranged so that the pressure upon the liquid fuel supply is relieved when a rise of temperature due to the heating action of the burner occurs, but that when the temperature falls again the pressure may be increased by means of the air compressor or the like. It is a further object of the invention to provide such a device that it may be set so as to maintain any desired temperature within the circulating hot water system or the like heated by the burner.

According to the present invention, a system for supplying liquid fuel from a con tainer maintained under pressure to a burner arranged to heat water is provided with a thermostatic device directly responsive to variations of temperature in the circulating hot water, heater or furnace, and arranged to relieve the pressure upon the liquid in the oil or other fuel container on arise of temperature in the circulating hot water heater or furnace occurring. In this manner when there is any appreciable rise in temperature beyond that for which the device is set, the

supply of oil is proportionately diminished,

falling off entirely should a stoppage of current or other cause interrupt the opera tion of the motor, acting in this way not only as a control butalso as an effective safety device. In systems in which the heated water is circulated and'returned to the heater, for example if the hot water is used for heating radiators, the thermostatic device may most conveniently be inserted either in the return feed pipe to or outlet the container is preferably effected by mak- I ing thetemperature-controlled element actuate a sleeve valve or similar, ported member in the container, an essential condition being that the outlet port shall be larger in cross section than the passage through which air is pumped to the oil container. Preferably, in order to prevent the escape into the atmosphere of air charged with oil in the gaseous condition, the escaping air'is led by a pipe to the suction side of the rotary compressor, and the gases are thus returned to the container.

In a preferred form of the invention, a simple air pressure chamber is inserted in the furnace, water space of the heater or return feed line, and by means of a small connecting pipe to the thermostat device, the corresponding variations in air pressure are caused to. move a diaphragm which carries a light sleeve-shaped member in accordance with the variations of pressure. This member has two or more holes made in it and its movement over a hollow cylindrical member, theinterior of which is in communication with the oil container, causes these holes to be brought into or out of alignment with similar holes in the cylindrical member. On a rise of temperature in the furnace, heater or circulating fluid there is a rise in pressure in the air pressure chamber-which produces a movement of the diaphragm, and thus brings into line the holes in the two members. Air at once escapes through these holes, and since their cross-sectional area is larger than that of the air admission passage, which is constructed as a branch pipe from the rotary blower, when the ports are completely in register air escapes at a faster rate than it is admitted. The pressure therefore drops and the feed of oil to the burner is curtailed or even interrupted. In this 7 way, over-heating of the furnace and heater is completely prevented. The diaphragm can-conveniently be arranged so that it may be set for a given temperature by raising or lowering it initially relatively to the member carried by'the container.

In order that the nature of the invention, and the manner in which it is to be performed, may be more completely understood, one system for supplying liquid fuel to a burner used for heating the heater of a hot water heating system, and embodying a thermostatic control device according to the present invention, will now be described with reference to the accompanying drawings, of which Figure 1 shows diagrammatically the fuel supply system and the heater furnace;

Figure 2 is a cross-section through the thermostatic control device, and

Figure 3 a plan of the same.

Referring first to Figure 1, oil is supplied from the reservoir 1 through the pipe 2 to the container 3 which is constructed of cast iron and is completely closed from the atmosphere. Mounted upon the top of this container is an electric motor 4 connected to a rotary air pump 5 which supplies the air required for the atomization and combustion of the oil fuel in the oil burner 6 by means of a pipe 7. A branch pipe 8 leads from the air delivery pipe 7 of the rotary air pump to the oil container 3, and serves to place the fuel in this container 3 under a small pressure, for example about two pounds per square inch. The pressure in the container 3 serves to expel the oil through the pipe 9 to the burner 6. This burner 6, which may advantageously be of a type which makes use of converging air jets impinging with high velocity upon a slow moving film of oil for producing atomization. of the fuel by impact in accordance with the specification of United States Patent No. 1,458,255, is located within the furnace chamber of a boiler 10 which may be of any suitable type. As shown, the burner is located in'the dead space of the heater 10, and is arranged so that the flame is directed downwardly.

An air pressure chamber 11 comprising a copper cartridge is placed in the Water pipe 12 which takes the return water to the heater 10. This air pressure chamber 11 is connected by a copper pipe 13 of fine bore to the top of a thermostatic control device 14 mounted upon the fuel container 3. It will be appreciated that the pipe 13 is merely shown diagrammatically in Figure 1, and in practice is made as short as possible.

This control device is shown in detail in Figures 2 and 3, and. consists of a cast iron casing 15 bolted to the top of the container 3, the joint being made as nearlyas possible airtight. "Within the casing 15 is carried a diaphragm 16 which is screwed between the flanged end of a pipe 17 and a disc 29. The central portion of the disc 29 is, of course, cut away, and the faces'of both flange and disc are machined so as to prevent any escape of air.

The pipe 17 has a very fine bore, and is connected directly on to the end of the pipe 13. It is most important to make the joint of these two pipes airtight, and for this purpose the end of the pipe 17 has a deep annular groove 30 turned in it, the central part 31 projecting from within this groove being of such a size as to fit within the enlarged end of the copper pipe 13. The joint is then made airtight by filling the groove 30 with melted solder.

The diaphragm 16 carries on its lower face, that is to say the face which is out of contact with the air pressure in the pipe 13, a valve member shown as a sliding sleeve 18 having two small holes 19. A hole 20 is cut in the top of the container 3, and projecting upwards immediately above this hole 20 from the face of the casing 15 is a small pipe 21 in the form of a hollow closed cylinder having two holes 22 in its side similar to the holes 19 of the sliding sleeve 18. This pipe 21 fits within the sleeve 18, and variations in the air pressure on t e diaphragm 16 cause this to move so as to bring the holes 19 and 22 into or out of alignment. A hole 23 is cut in the side of the casing 15, and this hole is made distinctly larger than the holes 19 and 22, so that when the diaphragm is depressed owing to a rise of pressure in the air pressure chamber 11 caused by a rise of temperature in the return feed water pipe 12, the holes 19 and 22 are brought partially into register and air can escape freely from the casing 15. In order to prevent the escape into the atmosphere of air charged with oil in the gaseous condition, the air escaping from the outlet 23 of the casing 15 is led through a pipe 32 to the suction inlet 33 of the rotary compressor 5, and the gases are in this way returned tothe container 3. The holes 19 and 22 are also made larger than the bore of'the pipe 8 which leads the compressed air to the fuel container 3, so that when they are completely in register air will escape faster from the container than it is admitted through the pipe 8. Further the holes 19 and 22 are made of such dimensions that they allow the air to escape rapidly and continuously with the result that a drop in the oil pressure at the burner 6 takes place immediately, and this pressure drop is followed by a corresponding temperature drop in the heater.

In order that the device may beset to maintain a given temperature in the heater 10, the end of the pipe 17 carrying the dia-' phragm is screw-threaded and a member 24- carrying a pointer 25 is screwed over this,

and fitted into the top of the casing. A groove 26 is cut in this member and a set screw 27 carried in the casing 15 engages in the groove 26 so that the member 24 cannot move vertically relatively to the casing 15. In consequence rotation of the member 24L causes the diaphragm 16 to be raised or lowered vertically, and it is guided by means of pillars 28 which engage in holes in the disc 29 to which it is screwed.

Although one form of the invention has been described in detail it is not, of course, limited to this. For example, the diaphragm may be replaced by a light movable springcontrolled piston from which the valve sleeve extends. Again, although the invention is articularly applicable to small hot water lieaters, it may, of course be used in connection with air heaters, the thermostatic device preferably then being inserted in the path of the heated air.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. An installation for supplying liquid fuel to a burner, comprising in combination with the burner a container for liquid fuel, means for maintaining under pressure the fuel in said container, a ported member carried by said container and in communication therewith, and a second ported member op eratively connected with a thermostatic element responsive to variations of temperature due to the heating action of said burner and (co-operating with said first ported member. I

2. An installation for supplying liquid fuel to a burner, comprising in combination with the fuel burner a container for liquid fuel, means for maintaining under pressure the fuel in said container, a ported member mounted upon said container and in com munication therewith, a thermostatic element responsive to variations of temperature due to the heating action of said burner, a diaphragm in operative connection with said thermostatic element and a second ported member carried by said diaphragm and cooperating with said first ported member.

3. An installation for supplying liquid fuel to a burner, comprising in combination with the burner a container for liquid fuel, means for maintaining under pressure the fuel in said container, a ported member mounted upon said container and in communication therewith, a thermostatic element responsive to variations of temperature due to the heating action of said burner, a dia phragm in operative connection with said thermostatic element, a second ported member carried by said diaphragm and coopcrating with said first ported member, and means for adjusting said diaphragm relatively to said first ported member.

4:. An installation for supplying liquid fuel to a burner, comprising in combination with the burner a container for liquid fuel, air compressing means for maintaining under pressure the fuel in said container, means for permitting the escapeof'air from said container, said means being operatively connected with a thermostatic element responsive to variations of temperature set up due to the heating action of said burner, and means for returning said escaping air to said air compressing means.

5. An installation for supplying liquid fuel to a burner, comprising in combination with the burner a container for liquid fuel, an air compressing machine for maintaining under pressure the fuel in said container, an air vent in said container, means for opening and closing said air vent, a thermostatic element responsive to temperature variations set up by the heating action of said burner, and operatively connected with said means for opening and closing said air vent, and means for leading the air escaping from said vent to the suction side of the air compressing machine.

In witness whereof I hereunto subscribe my name this 7th day of March, A. D. 1927.

ERNEST ANDREW REID. 

